Method and device for manufacturing absorber

ABSTRACT

A manufacturing device is provided, within a range in the rotation direction of the upper half of an anvil roll, in the order from the upstream side in the rotation direction of the anvil roll, with a first sheet feeding unit, a recess forming unit, a particulate material feeding device, and a second sheet feeding unit and further a welding unit provided on the downstream side of the second sheet feeding unit in the rotation direction. The anvil roll has a large number of concaves, projections provided in a portion among the concaves, so as to surround each of the concaves, and a unit to suck air in the concaves. For each concave, the projections are minute dot-shaped projections arranged only in one row at intervals in the direction surrounding the concave.

TECHNICAL FIELD

The present invention relates to a device and a method for manufacturingan absorber to be used for an absorbent article, such as disposablediapers and sanitary napkins.

BACKGROUND ART

The absorbent article includes an absorbent and a liquid-pervious topsheet covering the front surface side of the absorber. Excretion liquidsuch as urine and menstrual blood passes through the top sheet and isabsorbed and held by the absorber. An absorber obtained by mixingsuperabsorbent polymer (SAP) particles with hydrophilic short fiberssuch as fluff pulp and being accumulated in a cotton form has beenwidely used. However, while ensuring a sufficient absorbable amount andin response to the request for further thinning, weight reduction, andcost reduction, various types of absorbers (hereinafter also referred toas cell absorbers) are proposed. Such absorber includes a large numberof cells (small chambers) which are surrounded by bonded portions of thefront surface side sheet and the back surface side sheet, and thesesheets are not bonded in each cell. Further, the cell containsparticulate materials including superabsorbent polymer particles (referto, for example, Patent Literatures 1 to 7 below).

Various manufacturing methods for the cell absorbers have been proposed(for example, refer to Patent Literatures 1 to 7 below). However, themethods are basically common in: forming a large number of receivingrecesses at intervals in the transfer process thereof while continuouslytransferring the first sheet to be one of the front surface side sheetand the back surface side sheet; then, feeding the particulate materialsincluding the superabsorbent polymer particles into the receivingrecesses; subsequently, covering a second sheet on the opening side ofthe receiving recesses of the first sheet; bonding portions among thereceiving recesses of the first sheet and the second sheet; and thencutting these bonded sheets intermittently at positions to be boundariesbetween the individual absorbers.

However, for example, in the case of manufacturing the absorber by themethod described in Patent Literature 3, when the portions among therecesses of the first sheet and the second sheet are bonded, if theparticulate materials are present between the first sheet and the secondsheet at the bonded portions, bonding failure (including both of thecase where portions to be bonded have low bonding strength and the casewhere the portions are not bonded at all) may occur.

For this problem, in the invention disclosed in Patent Literature 1, atechnique is proposed in which a large number of suction holes areprovided on a conveying surface of a roll on the first sheet side,discharge ports are provided between the respective adjacent suctionholes, recesses are formed in the first sheet by suction with thesuction holes, and particulate materials are fed on the first sheetwhile emitting air from the discharge ports. However, in this method, itis necessary to provide the air discharge ports in projections formingthe bonded portions, and therefore there is a problem that thearrangement and shape of the projections are limited. In addition,obviously the manufacturing facilities become complicated.

CITATION LIST Patent Literature

-   Patent Literature 1: WO/2012/108331-   Patent Literature 2: JP 2012-147957 A-   Patent Literature 3: JP 2007-130819 A-   Patent Literature 4: JP 63-283777 A-   Patent Literature 5: JP 2013-17565 A-   Patent Literature 6: JP 2012-500669 A-   Patent Literature 7: JP 2010-522595 A

SUMMARY OF INVENTION Technical Problem

In view of the above, the main object of the present invention is toprevent bonding failure of the sheets by a further simple method withoutrestriction on the arrangement and shape of the projections (in otherwords, bonded portions) of the anvil roll in manufacturing the cellabsorbers.

Solution to Problem

The representative aspects of the present invention that have solved theabove problems will be described below.

<First Aspect>

A device for manufacturing an absorber, comprising:

an anvil roll, which has a plurality of concaves arranged at intervalson an outer peripheral surface, projections provided in a portion amongthe concaves, so as to surround each of the concaves, a suction unitconfigured to suck air in the concaves, without a suction port ordischarge port in the portion among the concaves, and which isrotationally driven around a transverse rotational axis, and

the device further comprising a first sheet feeding unit, a receivingrecess forming unit, a particulate material feeding device, a secondsheet feeding unit and a welding unit in this order from the upstreamside in the rotation direction of the anvil roll within a range in therotation direction of the upper half of the anvil roll,

the first sheet feeding unit being configured to feed a continuousbelt-shaped first sheet made of a liquid pervious nonwoven fabric in therotation direction of the anvil roll along the outer peripheral surfaceof the anvil roll;

the receiving recess forming unit being configured to form receivingrecesses in the first sheet along the outer peripheral surface of theanvil roll, the receiving recesses being recessed in the concaves;

the particulate material feeding device being configured to drop andfeed particulate materials including superabsorbent polymer particlesfrom above to the receiving recesses of the first sheet wound around theanvil roll;

the second sheet feeding unit being configured to feed a continuousbelt-shaped second sheet in the rotation direction of the anvil roll,wind the second sheet around the outer side of the first sheet, andcover at least a range in the cross direction (CD) having the receivingrecesses of the first sheet, with the second sheet; and

the welding unit being configured to weld the first sheet and the secondsheet only at the projections while winding the first sheet and thesecond sheet around the anvil roll, and being provided on the downstreamside of the second sheet feeding unit in the rotation direction of theanvil roll,

wherein the suction unit sucks air in the concaves at least in a rangein the rotation direction from a feeding position of the particulatematerials to a feeding position of the second sheet, as the projections,dot-shaped projections are arranged only in one row at intervals in thedirection surrounding each of the concaves, the area of the tip endsurface of each dot-shaped projection is 8 mm² or less, the width in thedirection orthogonal to the arrangement direction is 4 mm or less, andperipheral edges of the receiving recesses in the first sheet coincidewith the edges on the receiving recess side of the dot-shapedprojections surrounding the receiving recesses.

(Function and Effect)

In such configuration where on the outer peripheral surface of the anvilroll for bonding the first sheet and the second sheet by welding, priorto bonding, forming of the receiving recesses of the first sheet,feeding of the particulate materials, and covering with the second sheetare performed. At least from feeding of the particulate materials tocovering with the second sheet, a basic mode is carried out where theinside of each concave of the anvil roll is sucked. The projections ofthe anvil roll are intentionally set to small dot-shaped projections andprovided in a portion among the concaves only in one row at intervals inthe direction surrounding each of the concaves. The peripheral edge ofeach receiving recess in the first sheet coincides with the edges on thereceiving recess side of the dot-shaped projections surrounding thereceiving recess. In this case, since the projections have small dotshapes, it is basically difficult for the particulate materials to beplaced on the positions overlapping the projections of the anvil roll inthe first sheet. In addition, since each receiving recess formed in thefirst sheet becomes a receiving recess which is inclined from the inneredges of the projections surrounding the concave, the particulatematerials easily drop in the receiving recess by suction force, and theparticulate materials are likely to move to a deeper position.Furthermore, for each receiving recess, in the portion between each pairof the dot-shaped projections adjacent to each other in the directionsurrounding the concave, the first sheet is inclined toward the lowpoint at the center of the adjacent projections and inclined toward thereceiving recesses on the both sides of the portion (like a ridge ofconnected mountains), such that the particulate materials positioned inthe dot-shaped projections or in the vicinity thereof are more likely tomove toward the inside of the receiving recesses by the suction force.Therefore, the first sheet and the second sheet are bonded by welding ina simple technique of changing the pattern of the projections of theanvil roll, which makes it harder for the particulate materials to getcaught between the sheets at the bonded portions, and bonding failure ofthe sheets can be effectively prevented.

<Second Aspect>

The device for manufacturing an absorber according to the first aspect,comprising,

as the receiving recess forming unit, a pushing roll which is opposed tothe anvil roll, and which has push-in pins for entering the respectiveconcaves of the anvil roll,

wherein a continuous belt-shaped first sheet is passed in the rotationdirection of the anvil roll between the anvil roll and the push-in roll,and

the first sheet is pushed into the concaves with the push-in pins toform the receiving recesses in the first sheet.

(Function and Effect)

When the receiving recesses are formed by such a push-in roll, thereceiving recesses are formed more firmly. Therefore, it is preferablebecause the particulate materials more easily drop into the receivingrecesses.

<Third Aspect>

The device for manufacturing an absorber according to the first orsecond aspect, comprising a wave-forming device including,

a groove roll having a plurality of grooves continuing in the rollcircumferential direction and being arranged in the roll lengthdirection on the outer peripheral surface of the groove roll, a convexroll having a plurality of continuous convex portions continuing in theroll circumferential direction and being arranged in the roll lengthdirection on the outer peripheral surface of the convex roll, and aheating unit

wherein the groove roll and the convex roll being opposed to each othersuch that the grooves and the continuous convex portions are engagedwith each other, and

the heating unit heats the first sheet, which passes through between thegroove roll and the convex roll, to a melting temperature or lower,

wherein the first sheet is passed through between the groove roll andthe convex roll of the wave-forming device so that the first sheet issoftened by stretching in a waveform in the CD while being heated, andthen, the first sheet is fed to the anvil roll by the first sheetfeeding unit.

(Function and Effect)

If the first sheet is pretreated by such a wave-forming device, thefirst sheet is softened and becomes stretchable by the change in thefiber structure due to stretching of the first sheet. Therefore, thereceiving recesses can be formed further firmly in forming the receivingrecesses, in addition to this,

the first sheet is firmly sucked into the concaves by suction such thatthe first sheet becomes to have a surface shape further easier to dropin the receiving recesses, and thus this aspect is preferable.

<Fourth Aspect>

The device for manufacturing an absorber according to the third aspect,wherein the pushing depth of the first sheet by the push-in pin is 2 to10 mm, and in the wave-forming by the wave-forming device, the waveheight is 1 to 8 mm, and the peak-to-peak interval in the CD is 1 to 5mm

(Function and Effect)

To what extent the receiving recess are formed by the push-in roll andto what extent the wave-forming is performed can be appropriatelydetermined, but in the usual case, it is desirable to set them withinsuch a range.

<Fifth Aspect>

The device for manufacturing an absorber according to the first tofourth aspects, wherein the feeding position of the particulatematerials by the particulate material feeding device is disposed in arange having the rotation angle, with the vertically upward direction as0°, of 30° or more, and an angle formed by a horizontal plane and aridge line positioned on the most downstream side in the rotationdirection of the receiving recess of the first sheet is 0° or more.

(Function and Effect)

When the particulate materials are dropped and fed onto the first sheetat such a position, even if the particulate materials drop to a positioncorresponding to the projection of the anvil roll in the first sheet,the particulate materials are likely to drop on the downstream side inthe rotation direction, such that the particulate materials do noteasily stay at the position corresponding to the projection. Further,the receiving recess is oriented sideways, which makes difficult tocause a situation in which the particulate materials in the receivingrecess to move to the position corresponding to the projection of theanvil roll.

<Sixth Aspect>

A method for manufacturing an absorber using manufacturing device whichcomprises:

an anvil roll, which has a plurality of concaves arranged at intervalson an outer peripheral surface, projections provided in a portion amongthe concaves, so as to surround each of the concaves, a suction unitconfigured to suck air in the concaves, without a suction port ordischarge port in the portion among the concaves, and which isrotationally driven around a transverse rotational axis,

the device further comprising a first sheet feeding unit, a receivingrecess forming unit, a particulate material feeding device, a secondsheet feeding unit and a welding unit in this order from the upstreamside in the rotation direction of the anvil roll within a range in therotation direction of the upper half of the anvil roll,

the first sheet feeding unit being configured to feed a continuousbelt-shaped first sheet made of a liquid pervious nonwoven fabric in therotation direction of the anvil roll along the outer peripheral surfaceof the anvil roll;

the receiving recess forming unit being configured to form receivingrecesses in the first sheet along the outer peripheral surface of theanvil roll, the receiving recesses being recessed in the concaves;

the particulate material feeding device being configured to drop andfeed particulate materials including superabsorbent polymer particlesfrom above to the receiving recesses of the first sheet wound around theanvil roll;

the second sheet feeding unit being configured to feed a continuousbelt-shaped second sheet in the rotation direction of the anvil roll,wind the second sheet around the outer side of the first sheet, andcover at least a range in the CD having the receiving recesses of thefirst sheet, with the second sheet; and

the welding unit being configured to weld the first sheet and the secondsheet only at the projections while winding the first sheet and thesecond sheet around the anvil roll, and being provided on the downstreamside of the second sheet feeding unit in the rotation direction of theanvil roll,

wherein the suction unit sucks air in the concaves at least in a rangein the rotation direction from a feeding position of the particulatematerials to a feeding position of the second sheet,

as the projections, dot-shaped projections are arranged only in one rowat intervals in the direction surrounding each of the concaves, the areaof the tip end surface of each dot-shaped projection is 8 mm² or less,the width in the direction orthogonal to the arrangement direction is 4mm or less, and peripheral edges of the receiving recesses in the firstsheet coincide with the edges on the receiving recess side of thedot-shaped projections surrounding the receiving recesses, and

the method comprising:

feeding the first sheet to the anvil roll by the first sheet feedingunit;

forming the receiving recesses on the first sheet by the receivingrecess forming unit;

feeding the particulate materials to the receiving recesses of the firstsheet by the particulate material feeding device;

overlapping the second sheet on the first sheet by the second sheetfeeding unit;

bonding the portions among the receiving recesses of the first sheet andthe second sheet by the welding unit to successively form a continuousseries of the absorbers in which a plurality of cells containing theparticulate materials are arranged; and

cutting the continuous series of the absorbers into individual absorbersat intervals in the machine direction (MD).

(Function and Effect)

The same functions and effects as those obtained in the first aspect areobtained.

Advantage Effects of Invention

According to the present invention, it is advantageous that bondingfailure of the sheets can be prevented by a further simple methodwithout restriction on the arrangement and shape of the protrusions (inother words, bonded portions) of the anvil roll in manufacturing thecell absorber.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view illustrating the inner surface of a tape-typedisposable diaper in a state where a diaper is spread.

FIG. 2 is a plan view illustrating the outer surface of a tape-typedisposable diaper in a state where a diaper is spread.

FIG. 3 is a cross-sectional view taken along line 6-6 in FIG. 1.

FIG. 4 is a cross-sectional view taken along line 7-7 in FIG. 1.

FIG. 5(a) is a cross-sectional view taken along line 8-8 in FIG. 1, andFIG. 5(b) is a cross-sectional view taken along line 9-9 in FIG. 1.

FIG. 6 is a cross-sectional view taken along line 5-5 in FIG. 1.

FIG. 7(a) is a fragmentary plan view of a main part of an absorber, andFIG. 7(b) is a cross-sectional view thereof taken along line 1-1.

FIG. 8 illustrates schematic plan views illustrating various arrangementexamples of cells.

FIG. 9 is a plan view of the absorber.

FIG. 10 is a plan view of the absorber.

FIG. 11 is a cross-sectional view taken along the line 2-2 in FIGS. 9and 10.

FIG. 12 is a flow diagram of facilities for manufacturing the absorber.

FIG. 13 is a cross-sectional view of a main part schematicallyillustrating the facilities for manufacturing the absorber.

FIG. 14(a) is a cross-sectional view of a main part of an anvil roll,and FIG. 14(b) is a plan view of an anvil roll in which the outerperipheral surface is spread in a plane.

FIG. 15 is a front view of a corrugating device.

FIG. 16(a) is a cross-sectional view of a main part of a push-in roll,and FIG. 16(b) is a plan view of the main part of a push-in roll inwhich the outer peripheral surface is spread in a plane.

FIG. 17 is a cross-sectional view of a main part schematicallyillustrating other facilities for manufacturing an absorber.

FIG. 18 is a longitudinal sectional view of a chute unit.

FIG. 19 is a cross-sectional view taken along line 3-3 of FIG. 18.

FIG. 20 is a cross-sectional view taken along line 4-4 of FIG. 19.

FIG. 21 is an enlarged cross-sectional view of a main part illustratingthe recess forming step.

FIG. 22 is an enlarged cross-sectional view of a main part illustratingthe step for feeding particulate materials.

FIG. 23 is an enlarged cross-sectional view of a main part illustratingthe second sheet coating process.

FIG. 24 is an enlarged cross-sectional view of a main part illustratingthe welding step.

FIG. 25 is a cross-sectional view of a main part schematicallyillustrating facilities in a blocked state by a first blocking body.

FIG. 26 is a cross-sectional view taken along line 4-4 of FIG. 19 andillustrates a blocked state by the first blocking body.

FIG. 27 is a cross-sectional view of a main part schematicallyillustrating the facilities in a blocked state by a second blockingbody.

FIG. 28 is a plan view of a continuous series of absorbers.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the accompanying drawings.

Example of Absorbent Article

FIGS. 1 to 6 illustrate examples of a tape-type disposable diaper, inwhich the reference sign X indicates the maximum width of the diaperexcluding the fastening tapes, and the reference sign L indicates themaximum length of the diaper. Each component member is fixed or bondedin the same manner as known diapers as necessary except for the fixingor bonded portion described below. As a unit for fixing or bonding, ahot melt adhesive or welding (heat welding, ultrasonic welding) can beselected as appropriate.

This tape type disposable diaper has a basic structure in which anabsorber 50 is interposed between a liquid pervious top sheet and aliquid impervious sheet located on the external surface side. The tapetype disposable diaper includes a ventral side end flap portion EF, adorsal side end flap portion EF, and a pair of side flap portions SF.The ventral side end flap portion EF and the dorsal side end flapportion EF are portions extending to the front side and the back side ofthe absorber 50 respectively and not including the absorber 50. The pairof the side flap portions SF extends laterally from the side edges ofthe absorber 50. In each of the side flap portions SF in a dorsal sideportion B, a fastening tape 13 is provided. When a user wears thediaper, the fastening tape 13 is engaged at an appropriate place on theexternal surface of the ventral side portion F in a state in which theside flap portion SF of the dorsal side portion B is overlaid on theexternal side of the side flap portion SF of the ventral side portion F.

In this tape type disposable diaper, the entire external surface of theabsorbent main unit 10 and the respective side flap portions SF isformed by an outer sheet 12. Particularly, in a region including theabsorber 50, a liquid impervious sheet 11 is fixed to the internalsurface side of the outer sheet 12 with an adhesive such as a hot meltadhesive. Further, the absorber 50, an intermediate sheet 40, and a topsheet 30 are stacked in this order on the internal surface side of theliquid impervious sheet 11. In the illustrated example, the top sheet 30and the liquid impervious sheet 11 are rectangular in shape and havesomewhat larger sizes in the front-back direction LD and the widthdirection WD than the absorber 50. The peripheral edge portionsprotruding from the side edges of the absorber 50 in the top sheet 30and the peripheral edge portions protruding from the side edges of theabsorber 50 in the liquid impervious sheet 11 are bonded by a hot meltadhesive or the like. Further, the liquid impervious sheet 11 is formedto be slightly wider than the top sheet 30.

On the both sides of the absorbent main unit 10, three-dimensional sidegathers 60 and 60 projecting (standing) to the skin side of a wearer areprovided, and gather sheets 62 and 62 forming the three-dimensional sidegathers 60 and 60 are fixed in ranges on the both sides of the top sheet30 to the inner surfaces of the side flap portions SF.

Details of each part will be described in order below.

(Outer Sheet)

The outer sheet 12 is a sheet constituting the external surface of aproduct. The outer sheet 12 has a shape in which the intermediateportions in the front-back direction LD on the both side portions arenarrowed, and these portions surround the wearer's legs. A nonwovenfabric is suitable for the outer sheet 12, but it is not limitedthereto. The type of the nonwoven fabric is not particularly limited. Asa raw material fiber, for example, in addition to synthetic fibers suchas olefin type such as polyethylene or polypropylene, polyester type,and polyamide type, regenerated fibers such as rayon and cupra, andnatural fibers such as cotton can be used. As a processing method, aspun lace method, a spun bond method, a thermal bond method, an airthrough method, a needle punch method, and the like can be used.However, a long-fiber nonwoven fabric such as a spunbonded nonwovenfabric, an SMS nonwoven fabric, and an SMMS nonwoven fabric arepreferable in that both good texture and strength can be compatible. Inaddition to using a single piece of nonwoven fabric, it is also possibleto use multiple nonwoven fabrics in layers. In the latter case, it ispreferable that the nonwoven fabrics are adhered to each other with ahot melt adhesive or the like. When a nonwoven fabric is used, the basisweight of the fiber is desirably 10 to 50 g/m², particularly desirably15 to 30 g/m². The outer sheet 12 can be omitted, and in that case, theliquid impervious sheet 11 can have the same shape as that of the outersheet 12, such that the outer surface of a product can be formed.

(Liquid Impervious Sheet)

Although the material of the liquid impervious sheet 11 is notparticularly limited, for example, an olefin resin such as polyethyleneor polypropylene, a laminated nonwoven fabric obtained by stacking anonwoven fabric on a polyethylene sheet or the like, a nonwoven fabricin which liquid permeability is substantially secured through a waterproof film (in this case, a liquid impervious sheet is formed by thewaterproof film and the nonwoven fabric) can be exemplified. Obviously,besides this, in recent years, liquid impervious and moisture permeablematerials which have been favorably used from the standpoint ofprevention of stuffiness can also be exemplified. As a sheet of thisliquid-impervious and moisture-permeable material, for example, amicroporous sheet can be exemplified which is obtained by kneading anolefin resin such as polyethylene resin or polypropylene resin and aninorganic filler, forming a sheet with the kneaded materials andmonoaxially or biaxially stretching the sheet. Further, nonwoven fabricsusing micro denier fibers and a sheet that is liquid impervious withoutusing a water proof film can also be used as the liquid impervious sheet11. The sheet has liquid impermeability by having high leak proof byreducing air gaps of fibers by heating or applying pressure and byapplying a superabsorbent resin, a hydrophobic resin, or a waterrepellent agent.

(Top Sheet)

As the top sheet 30, a porous or non-porous nonwoven fabric havingliquid permeability can be used. The type of constituent fibers of thenonwoven fabric is not particularly limited. Examples of the nonwovenfabric can include synthetic fibers such as olefin type such aspolyethylene and polypropylene, polyester type, and polyamide type,regenerated fibers such as rayon and cupra, natural fibers such ascotton, mixed fibers and conjugate fibers in which two or more of theseare used, and the like. Further, the nonwoven fabric may be manufacturedby any processing. Examples of processing methods can include knownmethods such as a spun lace method, a spun bond method, a thermal bondmethod, a melt blown method, a needle punch method, an air throughmethod, and a point bond method. For example, the spun lace method ispreferable when flexibility and drapeability are required, and thethermal bonding method is preferable when bulkiness and softness arerequired.

(Intermediate Sheet)

The intermediate sheet 40 is bonded to the back surface of the top sheet30 to promptly move excretion liquid passing through the top sheet 30 tothe side of the absorber 50 and to prevent returning. For bondingbetween the intermediate sheet 40 and the top sheet 30, heat embossingor ultrasonic welding can be used in addition to using a hot meltadhesive. As the intermediate sheet 40, a resin film having a largenumber of through holes can be used in addition to using a nonwovenfabric. As the nonwoven fabric, a material similar to that described inthe section of the top sheet 30 can be used. However, the materialhaving a higher hydrophilicity than that of the top sheet 30 or thematerial having a high fiber density is preferable since those haveexcellent liquid transfer characteristics from the top sheet 30 to theintermediate sheet 40.

Although the intermediate sheet 40 in the illustrated embodiment isshorter than the width of the absorber 50 and disposed at the centerportion, it may be provided throughout the maximum width. The length ofthe intermediate sheet 40 in the front-back direction LD may be the sameas the maximum length of the diaper, may be the same as the length ofthe absorber 50, or may be within a short length range around a regionreceiving a liquid.

(Three-dimensional Side Gather)

To prevent lateral movement of excrement on the top sheet 30 and toprevent lateral leakage, it is preferable to provide thethree-dimensional side gathers 60 projecting (standing) from the innerfaces on the both sides of the product in the width direction WD.

Each three-dimensional side gather 60 is composed of gather sheet 62 andone or plurality of elongated elastically stretchable members 63 fixedto the gather sheet 62 in a stretched state along the front-backdirection LD. As this gather sheet 62, a water repellent nonwoven fabriccan be used, and rubber thread and the like can be used as theelastically stretchable member 63. As shown in FIGS. 1 and 3, aplurality of the elastically stretchable members may be provided on eachside, or only one elastically stretchable member may be provided on eachside.

The inner surface of the gather sheet 62 has a fixed start point in thewidth direction WD on the side portion of the top sheet 30. A portionoutside in the width direction WD from this fixed start point is fixedwith a hot melt adhesive or the like on the side portion of the liquidimpervious sheet 11 and the side portion of the outer sheet 12positioned at the outside portion.

In the periphery of the leg, the inside in the width direction WD fromthe fixed start point of each three-dimensional side gather 60 is fixedon the top sheet 30 at both ends of the product in the front-backdirection LD. However, the portion therebetween is a non-fixed freeportion erected by contraction force of one or a plurality of theelastically stretchable members 63. Since the diaper is attached to thebody in a boat shape in the wearing of the diaper, and the contractionforce of one or a plurality of the elastically stretchable members 63acts, the three-dimensional side gathers 60 erect by the contractionforce of one or a plurality of the elastically stretchable members 63and come in close contact with the legs. As a result, so-called lateralleakage from around the legs is prevented.

Unlike the illustrated embodiment, both end portions in the front-backdirection LD in the portion of the inside in the width direction WD ofeach gather sheet 62 are fixed in a state folded in two having a baseend side portion, which extends inward from a portion outside in thewidth direction WD and a tip side portion, which is folded back on thebody side from the end edge on the center side in the width direction WDof the base end side portion and extending outward in the widthdirection WD, and the portion therebetween may be a non-fixed freeportion.

(Flat Gather)

As illustrated in FIGS. 1 to 3, in each side flap portion SF, on theoutside in the width direction WD in the vicinity of the fixed startpoint of the fixed portion of the gather sheet 62, between the gathersheet 62 and the liquid impervious sheet 11, the elastically stretchablemembers 64, which are made of rubber threads and the like, around theleg portions are fixed in a state stretching along the front-backdirection LD, whereby the leg portion of each side flap portion SF isformed as a flat gather. The elastically stretchable members 64 aroundeach leg portion can also be disposed between the liquid impervioussheet 11 and the outer sheet 12 in the side flap portion SF. As in theillustrated example, a plurality of elastically stretchable members 64around the leg portions may be provided on each side, or only oneelastically stretchable member 64 may be provided on each side.

(Fastening Tape)

As illustrated in FIGS. 1, 2, and 6, each fastening tape 13 includes asheet base material forming a tape attaching portion 13C fixed to theside portion of a diaper and a tape main unit section 13B projectingfrom the tape attaching portion 13C, and an engagement portion 13A withrespect to the ventral side, which is provided in the middle portion inthe width direction WD of the tape main unit section 13B in the seatbase material. A tip end side from the engagement portion 13A is a tabpart. The tape attaching portion 13C of the fastening tape 13 issandwiched between the gather sheet 62 forming the inner layer in theside flap portion and the outer sheet 12 forming the outer layer and isadhered to the both sheets 62 and 12 with the hot melt adhesive. Inaddition, the engagement portion 13A is bonded to the sheet basematerial with an adhesive so that it cannot be removed.

A hook member (male member) of a mechanical fastener (hook and loopfastener) is suitable as the engagement portion 13A. The hook member hasa large number of engagement projections on its outer surface side. Theengagement projection has a check mark shape, a J shape, a mushroomshape, a T shape, and a double J shape (a shape bonded back to back of aJ shape), but may have any shape. Obviously, an adhesive material layercan also be provided as an engagement portion of the fastening tape 13.

In addition to various nonwoven fabrics such as a spunbonded nonwovenfabric, an air-through nonwoven fabric, and a spunlace nonwoven fabric,a plastic film, a polyethylene laminated nonwoven fabric, paper, or acomposite material thereof can be used as the sheet base materialforming from the tape attaching portion to the tape main unit section.

(Target Sheet)

It is preferable to provide a target sheet 12T having a target forfacilitating engagement at the engagement portion of each fastening tape13 in the ventral side portion F. In the case where the engagementportion is the hook member 13A, the target sheet 12T can be used havinga large number of loops made of threads to which engagement projectionsof the hook member are tangled, are provided on a surface of the sheetbase member made of a plastic film or a nonwoven fabric. Further, in thecase of an adhesive layer, it is possible to use a sheet base materialmade of a plastic film having a smooth surface with high adhesivenessand subjected to a release treatment. In the case where the engagementportion of the fastening tape 13 in the ventral side portion F is madeof a nonwoven fabric, for example, when the outer sheet 12 in theillustrated embodiment is made of a nonwoven fabric, and the engagementportion of the fastening tape 13 is the hook member 13A, the targetsheet 12T may be omitted, and the hook member 13A can be entangled andengaged with the nonwoven fabric of the outer sheet 12. In this case,the target sheet 12T may be provided between the outer sheet 12 and theliquid impervious sheet 11.

(Absorber)

The absorber 50 is a part that absorbs and retains the liquid content ofexcrement. The absorber 50 can be adhered to the components on at leastone of the front surface side and back surfaces side via an adhesivesuch as a hot melt adhesive.

As illustrated in the enlarged view of FIG. 7, the absorber 50 issurrounded by the front surface side sheet 51, the back surface sidesheet 52 disposed on the back surface side of the front surface sidesheet 51, and the bonded portions 54 of the front surface side sheet 51and the back surface side sheet 52, and also the absorber 50 is a cellabsorber 50 including a cell (small chamber) 55, in which the frontsurface side sheet 51 and the back surface side sheet 52 are not bonded,and the superabsorbent polymer particles 53 contained in the cell 55. Inthis way, by distributing and retaining the superabsorbent polymerparticles 53 in a large number of cells 55 surrounded by the bondedportions 54, the uneven distribution of the superabsorbent polymerparticles 53 in the absorber 50 can be prevented. The cell absorber 50can be wrapped with a wrapping sheet (not shown). In this case, onewrapping sheet can be used for wrapping the absorber in a cylindricalshape so as to surround the front and back surfaces and both sidesurfaces of the absorber 50 and two wrapping sheets can be also used forwrapping the absorber so as to sandwich the same from both the frontsurface side and the back surface side. As the wrapping sheet, a tissuepaper, particularly a crepe paper, a nonwoven fabric, a polyethylenelaminated nonwoven fabric, a sheet with small holes, and the like can beused. However, it is desirable that the wrapping sheet be a sheetthrough which superabsorbent polymer particles do not pass. When anonwoven fabric is used for a wrapping sheet, a hydrophilic SMS nonwovenfabric (SMS, SSMMS, etc.) is particularly suitable, and polypropylene,and polyethylene/polypropylene composite material can be used as amaterial. The basis weight is preferably 5 to 40 g/m², particularlypreferably 10 to 30 g/m². When the cell absorber 50 is wrapped with awrapping sheet, pulp fibers can be accumulated on one side of the frontand back sides of the cell absorber, and these can be wrapped with awrapping sheet collectively.

The front surface side sheet 51 may be a liquid-pervious material or aliquid impervious material, but preferably it is a liquid-perviousmaterial when it is positioned on the top sheet 30 side as indicated inthe illustrated embodiment. Similarly to the top sheet 30, a porous ornon-porous nonwoven fabric or a porous plastic sheet can be used for thefront surface side sheet 51. In the case of using a nonwoven fabric forthe front surface side sheet 51, examples of the constituent fibersinclude synthetic fibers (including not only single component fibers butalso conjugate fibers) such as olefin type such as polyethylene orpolypropylene, polyester type, and polyamide type, regenerated fiberssuch as rayon and cupra, and natural fibers such as cotton, but it canbe selected without limitation, and it is preferable to use athermoplastic resin fiber because of excellent thermal processability.The fiber bonding method of the nonwoven fabric is not particularlylimited, but to prevent the superabsorbent polymer particles 53 fromfalling off through the sheet, it is preferable to use a bonding methodwhich increases fiber density, such as a spun bond method, a melt blownmethod, and a needle punch method. In the case of using a porous plasticsheet, its pore diameter is preferably smaller than the outer shape ofthe superabsorbent polymer particle 53 to prevent the superabsorbentpolymer particle 53 from falling off through the sheet. When thematerial of the front surface side sheet 51 is hydrophobic, ahydrophilic agent can also be contained.

To facilitate the arrangement of the superabsorbent polymer particles 53in the manufacturing and to secure the volume after the swelling due tothe absorption, in the portion forming each cell 55 in the front surfaceside sheet 51, a recess 51 c recessed from the back surface side to thefront surface side is preferably formed.

The back surface side sheet 52 may be made of the same material as thefront surface side sheet 51, but in the case where the front surfaceside sheet 51 is composed of a liquid pervious material, a liquidimpervious material can be used for the back surface side sheet 52. Theliquid impervious material usable for the back surface side sheet 52 canbe appropriately selected and used from the materials described in thesection of the liquid impervious sheet 11. Although not illustrated, thefront surface side sheet 51 and the back surface side sheet 52 may beone side layer and another side layer in which one sheet of material isfolded in two.

The superabsorbent polymer particles 53 may not be fixed to the frontsurface side sheet 51 and the back surface side sheet 52 and may befreely movable, but may also be bonded or adhered to the front surfaceside sheet 51 and the back surface side sheet 52. Also, thesuperabsorbent polymer particles 53 may be agglomerated to some extent.

As the superabsorbent polymer particles 53, those used for this type ofabsorbent articles can be used on an as is basis. The particle diameterof the superabsorbent polymer particles is not particularly limited, butfor example, when the particles are sieved (shaking for five minutes)using a standard sieve (JIS Z8801-1:2006) of 500 μm and the particlessubjected to sieving with the 500 μm standard sieve are further sieved(shaking for five minutes) using the standard sieve (JIS Z8801-1: 2006)of 180 μm, preferably the proportion of the particles remaining on the500 μm standard sieve is 30% by weight or less, and the proportion ofthe particles remaining on the 180 μm standard sieve is 60% by weight ormore.

The material of the superabsorbent polymer particles 53 can be usedwithout particular limitation, but the material having the waterabsorption capacity of 40 g/g or more is suitable. Examples of thesuperabsorbent polymer particles 53 include starch-based,cellulose-based, and synthetic polymer-based, and starch-acrylic acid(salt) graft copolymers, saponified starch-acrylonitrile copolymers,sodium carboxymethyl cellulose crosslinked products, acrylic acid (salt)polymers and the like. As the shape of the superabsorbent polymerparticles 53, the shape of particulate materials which are usually usedis suitable, but other shapes can also be used.

The superabsorbent polymer particles 53 having a water absorption rateof 70 seconds or less, particularly 40 seconds or less, are suitablyused. If the water absorption rate is too slow, so-called returning, inwhich the liquid fed into the absorber 50 returns to the outside of theabsorber 50, is likely to occur.

The superabsorbent polymer particles 53 having the gel strength of 1,000Pa or more are preferably used. Thereby, even when the absorber 50 isbulky, it is possible to effectively suppress stickiness after liquidabsorption.

The basis weight of the superabsorbent polymer particles 53 can beappropriately determined according to the absorption amount required forthe use of the absorber 50. Therefore, although it cannot be saidunconditionally, the basis weight can be 50 to 350 g/m². When the basisweight of the polymer is less than 50 g/m², it is difficult to securethe absorption amount. When it exceeds 350 g/m², the effect issaturated.

The planar shape of the cell 55 can be determined as appropriate, and itmay be circular, elliptical, or the like, but the shape is preferably apolygon to provide a denser arrangement. In addition to arranging thecells 55 having the same shape and the same size, the cells 55 may bearranged by combining multiple types of cells varying at least one ofthe shape and size.

Although the planar arrangement of the cells 55 (that is, also thecollecting portions of the superabsorbent polymer particles 53) can beappropriately determined, a regularly repeated plane arrangement ispreferred. In addition to the regularly repeated plane arrangement, suchas an oblique lattice shape as illustrated in FIG. 8(a), a hexagonallattice shape (also referred to as a staggered shape) as illustrated inFIG. 8(b), a square lattice shape as illustrated in FIG. 8(c), arectangular lattice shape as illustrated in FIG. 8(d), and a parallellattice shape as illustrated in FIG. 8(e) (two groups of many paralleloblique direction rows are provided so as to cross each other)(including those inclined at an angle of less than 90° with respect tothe stretchable direction), a group of the cells 55 (the group may beregularly or irregularly arranged, and may be a pattern or a lettershape) can be regularly repeated.

The size of each cell 55 can be appropriately determined, and forexample, the length 55L in the front-back direction LD can be about 8 to30 mm, and the length 55W in the width direction WD can be about 10 to50 mm

It is desirable that the bonded portion 54 for bonding the front surfaceside sheet 51 and the back surface side sheet 52 be bonded by weldingthe front surface side sheet 51 and the back surface side sheet 52 likeultrasonic welding or heat sealing, but it may be bonded with a hot meltadhesive.

As long as each cell 55 is surrounded by one or a plurality of bondedportions 54 for bonding the front surface side sheet 51 and the backsurface side sheet 52, the bonded portions 54 may be arranged in adotted line shape (intermittently in a direction surrounding each cell55) as indicated in the illustrated embodiment and the bonded portionalso may be formed in a continuous linear shape. In the case ofintermittently forming the bonded portions 54, the superabsorbentpolymer particles 53 are not present between the bonded portions 54 inthe direction surrounding the cell 55, or even if the superabsorbentpolymer particles 53 are present, less superabsorbent polymer particlesthan those in the cell 55 are included.

The size of the bonded portion 54 for bonding the front surface sidesheet 51 and the back surface side sheet 52 can be appropriatelydetermined, and for example, the line width (dimension in the directionorthogonal to the direction surrounding the cell 55) 54W can be about0.6 to 8.0 mm. In the case of forming the bonded portions 54 in a dottedline shape (intermittent in the direction surrounding the cell 55), itis preferable that the length 54L of the bonded portion 54 in thedirection surrounding the cell 55 is about 0.6 to 8.0 mm, and the pointinterval 54D is about 0.8 to 10.0 mm. In particular, in the case of thestrong bonded portion 54 a, it is preferable that the line width 54W isabout 1.0 to 4.0 mm, the length 54L of the bonded portion 54 is about1.5 to 4.0 mm, and the point interval 54D is about 0.8 to 2.5 mm. In thecase of the weak bonded portion 54 b, it is preferable that the linewidth 54W is about 0.6 to 3.5 mm, the length 54L of the bonded portion54 is about 0.6 to 2.5 mm, and the point interval 54D is about 1.0 to4.0 mm.

The width of the bonded portion 54 in the case where the bonded portion54 is formed in a continuous linear shape, and the line width 54W in thecase where the bonded portions 54 are formed in a dotted line shape areconstant in the direction surrounding the cell 55 and also can bechanged. In addition, in the case where the bonded portions 54 areformed in a dotted line shape, the shape of each bonded portion 54 canbe appropriately determined, and all of the bonded portions have thesame shape, or the bonded portions may have different shapes dependingon their positions. In particular, when each cell 55 has a polygonalshape, it is preferable to provide each bonded portion 54 at theintermediate position of each side of the polygon. Further, it ispreferable to provide each strong bonded portion 54 a at a position ofeach vertex, but it is preferable not to provide the weak bonded portion54 b at the position of each vertex so that the weak bonded portion 54 bcan be peeled off easily, resulting in smooth coalescing of the cells55. In the case where the bonded portion 54 is provided at the positionof each vertex, it is desirable that the bonded portion 54 has a radial(star) shape protruding in the direction of each side.

When the superabsorbent polymer particles 53 in each cell 55 are swollendue to the absorption to fill the inside of the cell 55, the frontsurface side sheet 51 and the back surface side sheet 52 are stronglybonded at the bonded portions 54 such that the bonded portions 54 arenot peeled off against the internal pressure. However, when thesuperabsorbent polymer particles 53 fill the inside of each cell 55,there is a possibility that the absorption amount and absorption rateare lowered due to inhibition by the swelling and so-called gelblocking. Therefore, it is preferable that, because of the swellingpressure due to the absorption by the superabsorbent polymer particles53 in each cell 55, the bonded portions 54 surrounding the cell 55 arepartly or totally peeled off, and the cell 55 coalesces with theadjacent cells 55 to form a larger cell 55. Such a function is realized,for example, by providing the weak bonded portions 54 b with weakenedbonding strength in appropriate places and by determining the type andamount of the superabsorbent polymer particles 53 disposed in each cell55 such that the volume of the superabsorbent polymer particles 53 inthe cell 55 upon the saturation absorption becomes sufficiently largerthan the volume of the cell 55.

Although the bonding strength of the bonded portions 54 may be uniformover the entire absorber 50, as illustrated in FIGS. 7, 9, and 10, oneof the preferable embodiments is that the planar region of the absorber50 is divided into a plurality of compartments 55G, the bonded portions54 surrounding the group of the cells 55 of each compartment 55G areformed as strong bonded portions 54 a having relatively high bondingstrength, the bonded portions 54 located inside the compartment 55G areformed as weak bonded portions 54 b having relatively low bondingstrength, and the weak bonded portions 54 b are peeled off in preferenceto the strong bonded portions 54 a. In this case, all of the weak bondedportions 54 b in the compartment 55G are peeled off by the swellingpressure due to the absorption by the superabsorbent polymer particles53 in each cell 55 to form one cell 55 covering over the entirecompartment 55G, subsequently, the strong bonded portions 54 asurrounding the compartment 55G may be peeled off by the swellingpressure due to the absorption by the superabsorbent polymer particles53 in the compartment 55G. Instead, if the strong bonded portions arenot peeled off, the gelled material of the superabsorbent polymerparticles 53 swollen due to the absorption is hardly moved and gatheredto a low place such as a crotch portion, thus unsatisfactory fitting isnot caused. For example, in the embodiment illustrated in FIG. 9,assuming that urine is excreted at the position of the reference sign Z,urine is diffused around the position as illustrated in FIG. 10, and thesuperabsorbent polymer particles 53 absorb the urine at respectivepositions. At this time, as illustrated in FIGS. 10 and 11, with regardto each cell 55 in which the swelling pressure of the superabsorbentpolymer particles 53 is increased, the weak bonded portions 54 b aroundthe cell 55 cannot resist the swelling pressure and peels off and thecell 55 coalesces with the adjacent cells 55. This coalescence canproceed to reach the cells 55 having the strong bonded portions 54 atherearound as long as the weak bonded portions 54 b can be peeled offby the superabsorbent polymer particles 53 swollen due to theabsorption. Such a function is realized, for example, by determining thetype and amount of the superabsorbent polymer particles 53 disposed ineach cell 55 such that the volume of the superabsorbent polymerparticles 53 in the cell 55 upon saturation absorption becomessufficiently larger than the volume of each cell 55, and the volume ofthe superabsorbent polymer particles 53 in the compartment 55G uponsaturation absorption becomes less than the volume of the cells 55 ofthe entire compartment 55G surrounded by the strong bonded portions 54 aupon the coalescence.

Although the arrangement of the strong bonded portions 54 a is notparticularly limited, for example, as indicated in the illustratedembodiment, if the strong bonded portions 54 a continue throughout acertain range in a specific direction, such as the front-back directionLD, the width direction WD, and the oblique direction, the cells 55 onthe both sides are swollen due to the absorption by the internalsuperabsorbent polymer particles 53, the strong bonded portions 54 a arehowever not peeled off to the end. Therefore, after the absorption, thegrooves with the bottom portions of the strong bonded portions 54 a areformed along the specific directions, and the liquid diffusibility inthe directions along the grooves is improved. In addition, if the strongbonded portions 54 a continue in the width direction WD or in theoblique direction, it is possible to prevent the uneven distributionwhich would be caused by the movement of the gelled superabsorbentpolymer particles 53 swollen due to the absorption as well as to improvethe liquid diffusibility in the directions. Further, if the bondedportions positioned on the outermost side in the width direction WD arepeeled off, there is a possibility that the superabsorbent polymerparticles 53 or the gelled superabsorbent polymer particles 53 leak outlaterally from the absorber 50, and it is therefore desirable that suchbonded portions are the strong bonded portions 54 a. From the sameviewpoint, it is preferable that the front surface side sheet 51 and theback surface side sheet 52 are extended laterally in the width directionWD to some extent beyond the region where the cells 55 are formed, andthe edge bonded portions 54 c are provided in the extended portions forthe reinforcement.

The difference in bonding strength may be easily made by changing thearea of each bonded portion 54 but is not limited thereto. For example,in the case of forming the bonded portion 54 with a hot melt adhesive, amethod in which the type of a hot melt adhesive is varied depending onthe sites can be used.

As illustrated in FIG. 9, it is also possible to provide the empty cells56 which do not contain the superabsorbent polymer particles 53 or whichcontain a smaller amount of the superabsorbent polymer particles 53 thanother cells even if the cells contain them. In FIG. 9, an area 53Ahaving a pattern of hatched lines indicates a region for containing thesuperabsorbent polymer particles 53. Since this region is based onassumption of the shape of a region in which the superabsorbent polymerparticles 53 are dispersed in the manufacturing, there are portionswhich are not covered by the pattern of the hatched lines in the cells55 in the peripheral edge. Actually, in the case where thesuperabsorbent polymer particles 53 can move in each cell 55, thepositions of the superabsorbent polymer particles 53 in the cell 55 arenot fixed in a state of the product, and the superabsorbent polymerparticles 53 can be distributed throughout the cells 55 in the samemanner as in the state illustrated in FIG. 7. The amount of thesuperabsorbent polymer particles 53 contained in the empty cell 56 ispreferably ½ or less, particularly 1/10 or less, of the other cells interms of weight ratio, and it is particularly preferable that thesuperabsorbent polymer particles 53 are not contained at all in theempty cell. For example, since the front end and the back end of theabsorber 50 are formed by cutting into the individual absorbers 50 inthe manufacturing, if the superabsorbent polymer particles 53 arecontained in portions where the cutting is performed, the life of ablade of a cutting device may be shortened. Therefore, it is desirablethat at least the cells 55 located at the positions through which thefront and back ends of the absorber 50 pass be the empty cells 56.Further, in the absorber 50 obtained by mixing superabsorbent polymerparticles 53 with a hydrophilic short fiber such as fluff pulp, andbeing accumulated in a cotton form, generally, the intermediate portionin the front-back direction LD is formed in a narrow shape so as to bealong the legs. However, also in the cell absorber 50, by setting, thecells 55 on the both sides in the intermediate portion in the front-backdirection LD, as the empty cells 56, the intermediate portion in thefront-back direction LD will be less swollen even after the absorption.Therefore, the absorber 50 has a shape that fits around the legs evenafter the absorption.

In the case of manufacturing the absorber 50, since it is difficult toaccurately distribute a predetermined amount of the superabsorbentpolymer particles 53 to the individual cells 55, it is preferable thatthe superabsorbent polymer particles 53 are uniformly dispersedthroughout the entire region for containing the superabsorbent polymerparticles 53 (the region excluding the portions to be the empty cells56) on the front surface side sheet 51 or the back surface side sheet52, and then the bonded portions 54 are formed to bond the front surfaceside sheet 51 and the back surface side sheet 52 as one unit and toconfine the superabsorbent polymer particles 53 in each cell 55. In thiscase, particularly with respect to the peripheral cells 55 positioned inthe peripheral edge of the region for containing the superabsorbentpolymer particles 53, it is difficult to disperse the superabsorbentpolymer particles 53 in an accurate shape matching with the peripheraledge of the cells 55. Therefore, as can be seen from the shape of thedispersing region 53A which is defined for dispersing the superabsorbentpolymer particles 53 and indicated by the pattern of hatched lines inFIG. 9, it is desirable to disperse the superabsorbent polymer particles53 such that the peripheral edge of the region 53A for the dispersionpasses through the middle of the peripheral cells 55. In this case, theamount of the superabsorbent polymer particles 53 contained in theperipheral cells 55 is less than the amount of the same contained in thecells 55 positioned inside the peripheral cells 55, and in the casewhere the cells 55 are further provided outside the peripheral cells 55,these outer cells 55 become the empty cells 56 which do notsubstantially contain the superabsorbent polymer particles 53.

In the above example, only the superabsorbent polymer particles 53 arecontained in the cells 55, but it is also possible to contain thesuperabsorbent polymer particles 53 together with particulate materialsother than the superabsorbent polymer particles 53, such as deodorantparticles.

<Manufacturing of Absorber>

The above-described cell absorber 50 is manufactured by conveying acontinuous belt-shaped first sheet along a continuous direction,sequentially forming a large number of recesses on the first sheet inthis conveying process at intervals in the CD while the first sheet isconveyed, feeding particulate materials including superabsorbent polymerparticles to the recesses of the first sheet on the downstream side ofthe recess forming position, overlapping a belt-shaped second sheetcontinuous in the MD on the first sheet on the downstream side of thefeeding position of the particulate materials, bonding portions amongthe recesses of the first sheet and the second sheet on the downstreamside of the position where the second sheet is overlapped, sequentiallyforming a continuous series of the absorbers in which a large number ofcells containing particulate materials are arranged, and cutting acontinuous series of the absorbers into individual absorbers atintervals in the MD. Although it is preferable that the first sheet isthe front surface side sheet of the above-described cell absorber 50 andthe second sheet is the back surface side sheet, those may be setopposite.

FIG. 12 illustrates a specific example of a device for manufacturing thecell absorber. This manufacturing device is based on an anvil roll 70which is driven to rotate about a lateral rotating shaft. Within therotation direction range of the upper half of the anvil roll 70, in theorder from the upstream side in the rotation direction, the first sheetfeeding unit 80, a recess forming unit 90, a particulate materialfeeding device 100, and a second sheet feeding unit 150 are provided. Inaddition, a welding unit 160 is provided on the downstream side in therotation direction of the feeding unit of the second sheet.

As also illustrated in FIGS. 13 and 14, the anvil roll 70 has a largenumber of concaves 71 arranged at intervals on the outer peripheralsurface, and for each concave 71, projections 72 provided so as tosurround the concave 71 in a portion among the concaves 71. The concave71 on the outer peripheral surface of the anvil roll 70 communicateswith the inner space partitioned into a suction compartment 73 and anon-suction compartment 74 in the rotation direction. A suction devicesuch as a suction fan (not illustrated) is connected to the suctioncompartment 73 in the inner space of the anvil roll 70, and the insideof the concave 71 can be sucked. In addition, neither a suction port nora discharge port is formed in the portion among the concaves 71 on theouter peripheral surface of the anvil roll 70.

The first sheet feeding unit 80 feeds a continuous belt-shaped firstsheet 201 made of a liquid pervious nonwoven fabric in the rotationdirection of the anvil roll 70 along the outer peripheral surface of theanvil roll 70. The first sheet feeding unit 80 includes various devicessuch as a guide roll and a drive roll in a path from the material rollof the first sheet 201 (not illustrated) to the outer peripheral surfaceof the anvil roll 70.

It is preferable that the first sheet feeding unit 80 includes awave-forming device 81. As also illustrated in FIG. 15, the wave-formingdevice 81 includes a groove roll 82 having a large number of grooves 82g continuous in the roll circumferential direction and arranged in theroll length direction on the outer peripheral surface of the grooveroll, and a convex roll 83 having a large number of convex portions 83 pcontinuous in the roll circumferential direction and arranged in theroll length direction on the outer peripheral surface of the convexroll, while the groove roll 82 and the convex roll 83 are opposed toeach other such that the grooves 82 g and the continuous convex portions83 p are engaged with each other. Further, the wave-forming deviceincludes a heating unit 84, where the groove roll 82 and the convex roll83 pass, for heating the first sheet 201 to a melting temperature orlower. In the illustrated embodiment, the heating unit 84 is a heatingbox 84 which surrounds the convex roll 83 and the groove roll 82 andkeeps the internal atmosphere at a predetermined temperature, but aheating unit for heating at least one of the groove roll 82 and theconvex roll 83 may be used, or one heating unit for heating one of theserolls and the other heating unit for the other of these rolls may becombined. The temperature of the first sheet 201 in the wave-formingdevice 81 can be appropriately determined according to the type of thematerial, but it is preferable to set it at 40 to 100° C. assuming thecase of using a normal thermoplastic nonwoven fabric.

By the recess forming unit 90, the first sheet 201 may be recessed toreach at least the second sheet 202 feeding unit by taking air in theconcave 71 by the above-described suction unit. In the illustratedembodiment, as also illustrated in FIG. 16, as the recess forming unit90, a push-in roll 90 is provided. The push-in roll 90 opposed to theanvil roll 70 has push-in pins 91 which enter the respective concaves 71of the anvil roll 70. The push-in roll 90 forms receiving recesses 201 con the first sheet 201 by feeding the continuous belt-shaped first sheet201 in the rotation direction of the anvil roll 70 between the anvilroll 70 and the push-in roll 90 and pushing the first sheet 201 into theconcaves 71 by the push-in pins 91.

The particulate material feeding device 100 can be used withoutparticular limitation as long as it drops and feeds the particulatematerials 203 including the superabsorbent polymer particles 53. Here,the dropping and feeding includes free dropping under their own weightsor more than that. As the particulate material feeding device 100, thefollowing two types can be used: in one type, the particulate materialsare fed continuously over the entire CD of a drop position and inanother type, the particulate materials are fed intermittently at leasta part in the CD of the drop position.

FIG. 13 and FIGS. 18 to 20 illustrate specific examples of theparticulate material feeding device 100. The particulate materialfeeding device 100 includes the particulate material storage tank 101for storing the particulate materials 203, the delivery device 102 forcontinuously delivering the particulate materials 203 stored in theparticulate material storage tank 101, a chute 103 for dropping andtransferring the particulate materials 203 delivered from the deliverydevice 102 and dropping and feeding the particulate materials 203 to afeeding position, blocking bodies 104 and 105 which intermittently enterblocking positions for blocking at least a part of particulate passagein a cross-sectional direction in the chute 103, from a non-blockingposition, and a recovery path 106 branched from the chute 103 so as todischarge the particulate materials 203 blocked by the blocking bodies104 and 105 to the outside of the chute 103.

In the illustrated embodiment, as the delivery device 102 for deliveringthe particulate materials 203 from the particulate material storage tank101, a so-called rotary feeder 102 is connected to the lower end outletof the particulate material storage tank 101, and by this rotary feeder102, the particulate materials 203 stored in the particulate materialstorage tank 101 are continuously discharged and continuously andquantitatively fed to the chute 103. The delivery device 102 is notlimited to the rotary feeder 102, and other known particulate materialfeeding devices 100 can be used. Further, the particulate materials maynot be quantitatively supplied, for example, the feeding amount may becontinuously or gradually changed.

As long as the chute 103 drops and transfers the particulate materials203 to drop and feed the particulate materials 203 to the feedingposition, a part or the whole of the particulate materials 203 may bedropped without coming into contact with the peripheral wall or mayslide down on the peripheral wall. That is, the chute 103 may extendstraight in the substantially vertical direction as indicated in theillustrated embodiment, and it may have a curved portion or a bentportion that draws an arc in part or in whole, unlike the illustratedembodiment. The passage position in the cross-sectional direction in thechute 103 may be changed continuously or gradually in the transferdirection, but in the case where intermittent feeding is performed onlyin a part in the CD, the passage position is desirably not changed inthe CD or at least not reduced.

The blocking position of the blocking body 104, 105 is not particularlylimited as long as it is a position blocking at least a part of theparticulate passage in the sectional direction, but for example, theblocking position may be a position where the particulate passage in themiddle in the CD in the chute 103 is not blocked, the particulatepassage on the both sides is blocked, or a position where theparticulate passage throughout the entire cross-sectional direction inthe chute 103 is blocked. Alternatively, the first blocking body 104 maybe provided at one of these blocking positions, and the second blockingbody 105 may be provided on the other one.

As a drive mechanism for causing the blocking bodies 104 and 105 tointermittently enter the blocking position, the blocking bodies 104 and105 can be linearly reciprocated with respect to the blocking positionsby a crank mechanism or a fluid pressure cylinder, the blocking bodies104 and 105 can be rotated about one point by a rotary drive source suchas a motor to pass the rotational movement locus of the blocking bodies104 and 105 through the blocking position, or the blocking bodies 104and 105 can be rotated in parallel by the crank mechanism to pass therotational movement locus of the blocking bodies 104 and 105 through theblocking position.

The recovery path 106 is a passage having an inlet in a direction inwhich the particulate materials 203 collide with the blocking bodies 104and 105 and move, and the particulate materials 203 blocked by theblocking bodies 104 and 105 are discharged to the outside of the chute103 by the moving force of a suction fan or the like or under their ownweights. It is desirable that the blocked particulate materials 203collected via the recovery path 106 be returned to the particulatematerial storage tank 101 for reuse as indicated in the illustratedembodiment, but the blocked particulate materials 203 may be temporarilystored in a storage tank or a storing bag for reuse, or may not bereused.

The particulate material feeding device 100 in the illustratedembodiment will be described in further detail. The chute 103, theblocking bodies 104 and 105, and the recovery path 106 are included inone box type unit. This box-type unit has a top plate 111, a bottomplate 112, and a side plate 113 covering the periphery of a spacebetween the top plate 111 and the bottom plate 112. The box-type unithas a casing 110 arranged to be inclined with respect to the horizontaldirection, a chute feeding port 114 provided on the upper side in theinclination direction of the top plate, a chute discharge port 115provided on the lower side in the inclination direction of the chutefeeding port 114, and chute main unit sections 121 and 122 forconnecting these ports in the casing 110. A portion of the casing 110 onthe lower side in the inclination direction of the chute main unitsection 122 is a start point portion of the recovery path 106. The chutefeeding port 114, the chute main unit sections 121 and 122, and thechute discharge port 115 have a substantially rectangularcross-sectional surface whose long side extends along the CD. The chutemain unit sections 121 and 122 have a first passage 121 having an inletprovided below the chute feeding port 114 and extending in thesubstantially vertical direction from the inlet to a position above thefirst blocking position, and a second passage 122 having an inlet belowthe first blocking position and extending in the substantially verticaldirection from the inlet to a position above the second blockingposition on the chute discharge port 115.

The first passage 121 is a passage having a substantially rectangularcross-sectional surface formed with a pair of planes extending in the MDand a pair of planes extending in the CD. The second passage 122 is athrough section having a substantially rectangular cross-sectionalsurface formed below the first blocking position in the partition plate116 extending from the upper side to the lower side of the firstblocking position in the inclination direction. The space of the firstblocking position located between the outlet of the first passage 121and the upper face of the partition plate 116 and the space of thesecond blocking position located between the outlet of the secondpassage 122 and the chute discharge port 115 open in the recovery path106 on the obliquely lower side.

The first blocking body 104 in the illustrated embodiment comprisesblade bodies (such as impellers) provided on the both sides in the CD inthe first blocking position. Each black body is provided in a part ofthe rotation direction of a rotary shaft 104 s extending in a directionintersecting the inclination direction on both sides in the CD of thefirst blocking position. By rotating the rotary shaft 104 s by a rotarydrive source (not illustrated), the first blocking body 104 repeatsentering from the obliquely upper side and retracting from the obliquelylower side with respect to the both sides in the CD at the firstblocking position. When the first blocking body 104 is in the retractedposition, all of the particulate materials 203 dropping toward the inletof the second passage 122 are allowed to pass through. However, when theparticulate materials 203 pass through the first blocking position asindicated by rotation loca indicated by the two-dot chain lines in FIG.19, the blocking body 104 does not block the particulate passage in themiddle in the CD and blocks the particulate passage on the both sidesthereof, as illustrated in FIGS. 25 and 26. Therefore, the space at thefirst blocking position also opens to the side such that the firstblocking body 104 can enter and retract. The particulate materials 203blocked by the first blocking body 104 move on the first blocking body104 and the partition plate 116 and are introduced into the recoverypath 106 on the lower side in the inclination direction.

In addition, the second blocking body 105 in the illustrated embodimentis a blocking plate that is dimensioned to cover the entire chutedischarge port 115 and that extends along the inclination direction. Thesecond blocking body 105 is supported to be reciprocable in theinclination direction, and passes through the chute discharge port 115in the process. When the second blocking body 105 is in the retractedposition not covering the chute discharge port 115, all of theparticulate materials 203 dropping toward the chute discharge port 115are passed. When the second blocking body 105 passes through theblocking position on the chute discharge port 115, as indicated bytwo-dot chain lines in FIGS. 13 and 19 and illustrated in FIG. 27, allthe particulate materials 203 dropping toward the chute discharge port115 are blocked. The particulate materials 203 blocked by the secondblocking body 105 move on the second blocking body 105 and the bottomplate 112 and are introduced into the recovery path 106 on the lowerside in the inclination direction. The particulate materials 203discharged from the chute discharge port 115 are sequentially droppedand fed onto the first sheet 201 wound around the outer peripheralsurface of the anvil roll 70.

The second sheet feeding unit 150 disposed on the downstream side in therotation direction of the particulate material feeding device 100 feedsa continuous belt-shaped second sheet 202 made of a liquid perviousnonwoven fabric in the rotation direction of the anvil roll 70 along theouter peripheral surface of the anvil roll 70. The second sheet feedingunit 150 includes various devices such as a guide roll and a drive rollin a path from the material roll (not illustrated) of the second sheet202 to the outer peripheral surface of the anvil roll 70. In theillustrated embodiment, the guide plate 151, which approaches thevicinity of the outer peripheral surface of the anvil roll 70 in thetangential direction, is disposed, and the second sheet 202 passes overthe guide plate 151, is folded back at its tip, and is fed in therotation direction along the outer peripheral surface of the anvil roll70. Therefore, the tip end of the guide plate 151 is an arcuate surfaceof a curved surface extending along the guiding direction of the secondsheet 202.

The welding unit 160 is not particularly limited as long as it welds thefirst sheet 201 and the second sheet 202. In addition to using theultrasonic horn 160 of the ultrasonic welding apparatus as indicated inthe embodiment of FIG. 12, a heating roll 161 may be used as indicatedin the embodiment of FIG. 17.

In the manufacturing, as illustrated in FIGS. 13 and 21, the first sheet201 is supplied to the anvil roll 70 by the first sheet feeding unit 80,and the receiving recesses 201 c are sequentially formed in the firstsheet 201 by the recess forming unit 90. In this case, by forming thereceiving recesses 201 c by a push-in roll as indicated in theillustrated embodiment, the receiving recesses 201 c are formed morefirmly as compared with the case where the receiving recesses 201 c areformed by suction, and therefore it is preferable since the particulatematerials 203 easily drop into each receiving recess 201 c when theparticulate materials are fed. Prior to the feeding of the first sheet201 to the anvil roll 70, if the first sheet 201 is pretreated by thewave-forming device 81 as indicated in the illustrated embodiment, it issoftened and becomes stretchable by the change in the fiber structuredue to stretching of the first sheet 201. Therefore, in addition tofurther firmly forming the receiving recesses 201 c in forming thereceiving recesses 201 c, the first sheet 201 is firmly sucked into theconcaves 71 by suction such that the first sheet 201 becomes to have asurface shape easier to drop in the receiving recesses 201 c, and thusit is preferable. To what extent the receiving recess 201 c are formedby the push-in roll and to what extent the wave-forming is performed canbe determined as appropriate, but in the usual case, it is desirablethat the pushing depth 91 d of the first sheet 201 by the push-in pin 91be 2 to 10 mm, the wave height 81 h in wave-forming by the wave-formingdevice 81 be 1 to 8 mm, and the peak-to-peak interval 81 d of theadjacent waves in the CD be 1 to 5 mm

The first sheet 201 on which the receiving recesses 201 c is formed isrotated to the feeding position of the next particulate material feedingdevice 100 while being wound around the anvil roll 70. At this time,since the concaves 71 are located in the suction compartment 55G fromthe stage of forming the receiving recesses 201 c, and the concaves 71are continuously sucked, the receiving recesses 201 c are firmly held inthe concaves 71 while the receiving recesses remain their formed shapes.The sucking is continued at least to the second sheet 202 feedingposition, preferably to the welding position. As illustrated in FIGS. 13and 22, the particulate materials 203 are dropped and fed to eachreceiving recess 201 c of the first sheet 201 from the particulatematerial feeding device 100. The particulate materials 203 can becontinuously fed or intermittently fed in at least a part in the CD.

With respect to the first sheet 201 in which the particulate materials203 are fed to the receiving recesses 201 c, as illustrated in FIGS. 13and 23, the second sheet 202 is immediately wound around the outside ofthe first sheet 201 by the second sheet feeding unit 150, and the CDrange having at least the receiving recess 201 c of the first sheet 201is covered with the second sheet 202. While the first sheet 201 and thesecond sheet 202 are wound around the anvil roll 70, as illustrated inFIGS. 13 and 24, by the welding unit 160, portions among the receivingrecesses 201 c of the first sheet 201 and the second sheet 202 areimmediately welded and bonded at sites of the dot-shaped projections 72on the anvil roll 70 to sequentially form a continuous series 200 of theabsorbers 50 in which a large number of the cells 55 containing theparticulate materials 203 are arranged. After delivering the continuousseries 200 of the absorbers 50 from the anvil roll 70, it is cut intoindividual absorbers 50 at intervals in the MD by a cutting device (notillustrated).

The projections 72 of the anvil roll 70 can be formed in an appropriatepattern, but as illustrated in FIG. 14, the dot-shaped projections 72 ineach of which the area of the tip end surface is 8 mm² or less (largerthan 0 mm²) and the width 72W in the direction orthogonal to thedirection surrounding each concave 71 is 4 mm or less (longer than 0 mm)are arranged in only one row at intervals 72D in the directionsurrounding each concave 71. The peripheral edge of each receivingrecess 201 c in the first sheet 201 preferably coincides with the edgeson the receiving recess 201 c side of the dot-shaped projections 72surrounding the each receiving recess 201 c. The projections 72 areprovided for forming the bonded portions 54 in a product, and theirarrangement and dimension can be made almost the same as the bondedportions 54 in the product.

In this way, on the outer peripheral surface of the anvil roll 70 forbonding the first sheet 201 and the second sheet 202 by welding, priorto bonding, formation of the receiving recesses 201 c of the first sheet201, feeding of the particulate materials 203, and covering with thesecond sheet 202 are performed. At least from feeding of the particulatematerials 203 to covering with the second sheet 202, a basic mode iscarried out where the inside of each concave 71 of the anvil roll 70 issuctioned. As illustrated in FIGS. 14 and 22, the projections 72 of theanvil roll 70 are intentionally set to small dot-shaped projections 72and for each concave 71, arranged in one row at intervals in thedirection surrounding the concave 71 in the portion among the concaves71. The peripheral edge of each receiving recess 201 c in the firstsheet 201 coincides with the edges on the receiving recess 201 c side ofthe dot-shaped projections 72 surrounding the receiving recess 201 c. Inthis case, since the projections 72 have small dot shapes, it isbasically difficult for the particulate materials 203 to be placed onthe positions overlapping with the projections 72 of the anvil roll 70in the first sheet 201. In addition, since the receiving recesses 201 cformed in the first sheet 201 become the receiving recesses 201 c whichare inclined from the inner edges 72 e of the projections 72 surroundingthe concaves 71, the particulate materials 203 easily drop in thereceiving recesses 201 c by suction force indicated by the dotted arrowsin FIG. 22, and the particulate materials 203 in the receiving recesses201 c are likely to move to deeper positions. Furthermore, for eachreceiving recess 201 c, in the portion between each pair of thedot-shaped projections 72 adjacent to each other in the directionsurrounding the concave 71, the first sheet is inclined toward the lowpoint at the center of the adjacent projections and inclined toward thereceiving recesses 201 c on the both sides of the portion (like a ridgeof connected mountains), such that the particulate materials 203positioned in the dot-shaped projections 72 or in the vicinity thereofare more likely to move toward the inside of the receiving recesses 201c by the suction force. Therefore, when the first sheet 201 and thesecond sheet 202 are bonded by welding in a simple technique of changingthe pattern of the projections 72 of the anvil roll 70, which makes itharder for the particulate materials 203 to get caught between thesheets at the bonded portions 54, and bonding failure of the sheets canbe effectively prevented.

Although the feeding position by the particulate material feeding device100 is adjusted appropriately, as illustrated in FIG. 13, it isdesirable that the particulate materials 203 be dropped within a rangein which the rotation angle θ1 with the vertically upward direction as0° is 30° or more (more preferably 45° or more) in the rotationdirection of the anvil roll 70, and the angle θ2 formed by thehorizontal plane and the ridge line positioned on the most downstreamside in the rotation direction of the receiving recess 201 c of thefirst sheet 201 is 0° or more (more preferably 10° or more). When theparticulate materials 203 are dropped and fed onto the first sheet 201at such a position, even if the particulate materials 203 drop to aposition corresponding to the projection 72 of the anvil roll 70 in thefirst sheet 201, the particulate materials are likely to drop on thedownstream side in the rotation direction, such that the particulatematerials 203 do not easily stay at the position corresponding to theprojection 72. Further, the receiving recess 201 c is oriented sideways,which makes difficult to cause a situation in which the particulatematerials 203 in the receiving recess 201 c move to the positioncorresponding to the projection 72 of the anvil roll 70.

In addition, when the above-described particulate material feedingdevice 100 is used, it is possible to feed the following particulatematerials 203. That is, when the feeding position of the particulatematerial feeding device 100 is positioned in the intermediate portion inthe MD between the receiving recesses 201 c overlapping with each pairof the planned-cutting-positions into the individual absorbers 50 in thefirst sheet 201, the timing for the first blocking body 104 tointermittently enter the first blocking position is set so as to blockfeeding of the particulate materials 203 by the first blocking body 104.When the feeding position of the particulate material feeding device 100includes the receiving recesses 201 c overlapping with theplanned-cutting-position into the individual absorbers 50 in the firstsheet 201, the timing for the second blocking body 105 to enter thesecond blocking position is set so as to block feeding of theparticulate materials 203 by the second blocking body 105. As a result,as illustrated in FIG. 28, in the continuous series 200 of the absorbers50 to be manufactured, the cells 55 overlapping with each pair of theplanned-cutting-positions 210 to the individual absorbers 50 are theempty cells 56 containing no particulate materials 203 including thesuperabsorbent polymer particles 53, and therefore it is possible toprevent shortening the life of a blade of the cutting device. Also, inthe continuous series 200 of the absorbers 50, the cells 55 at thepositions 220 along the legs on the both sides in the intermediateportion in the front-back direction LD are also the empty cells 56containing no particulate materials 203 including the superabsorbentpolymer particles 53. Therefore, the portions are less swollen evenafter absorption, and even after the absorption, the absorber 50 isshaped to fit around the legs.

<Others>

Although the particulate material feeding device 100 of the aboveexample is used for feeding the particulate materials 203 including thesuperabsorbent polymer particles in manufacturing the cell absorbers 50,it can be also used in the case where layers of particles such assuperabsorbent polymer particles are laminated on the assembly of pulpfibers, a sheet of a nonwoven fabric or the like. Further, theparticulate material feeding device 100 of the above example can be usedin the case of using particulate materials other than superabsorbentpolymer particles such as deodorant particles instead of or togetherwith the superabsorbent polymer particles, in the case of theparticulate materials 203 that can be dropped and fed, and it can begenerally applied to the feeding of the particulate materials 203.

Explanation of Terms Used Herein

In the case where the following terms are used in the specification,those have the following meanings unless otherwise specified in thespecification.

“Machine direction (MD)” and “cross direction (CD)” mean the flowdirection (MD) in a manufacturing facility and the lateral direction(CD) orthogonal to the flow direction, and either one is the front-backdirection of a product, and the other is the width direction of theproduct. The MD of a nonwoven fabric is the direction of fiberorientation of the nonwoven fabric. “Fiber orientation” is a directionalong which a fiber of a nonwoven fabric runs and determined by, forexample, a measurement method in accordance with the fiber orientationtest method based on the zero span tensile strength of TAPPI T481 and asimple measurement method for determining the direction of the fiberorientation from the ratio of the tensile strength in the front-backdirection to the width direction.

“Spread state” means a flatly spread state without contraction or slack.

“Stretch rate” means the value when the natural length is taken as 100%.

“Artificial urine” is prepared by mixing urea: 2 wt %, sodium chloride:0.8 wt %, calcium chloride dihydrate: 0.03 wt %, magnesium sulfateheptahydrate: 0.08 wt %, and ion exchanged water: 97.09 wt %, and thoseare used at a temperature of 40° C. unless otherwise specified.

“Gel strength” is measured as follows: 1.0 g of superabsorbent polymersare added to 49.0 g of artificial urine and the mixture is stirred witha stirrer. The resulting gel is left for three hours in athermohygrostat bath at 40° C., 60% RH and then cooled to roomtemperature. The gel strength of the gel is measured with Curdmeter (MAXME-500, manufactured by I. Techno Engineering Co., Ltd).

“Basis weight” is measured as follows. After the sample or test piece ispreliminarily dried, it is allowed to stand in a test room or apparatusunder normal conditions (the test location is at a temperature: 20±5°C., relative humidity: 65% or less) until the constant mass. Thepreliminary drying is to make the sample or test piece be constant massin an environment within a relative humidity of 10 to 25% and at atemperature not exceeding 50° C. The fibers of an official moistureregain of 0.0% does not need preliminary drying. A cut sample with asize of 200 mm by 250 mm (±2 mm) is cut from the test piece in theconstant mass, with a cutting template (200 mm×250 mm, ±2 mm). Thesample is weighed and the weight is multiplied by 20 into the weight persquare meter. The resulting value is defined as the basis weight.“Thickness” is automatically measured under the conditions of a load of10 gf/cm² in a pressurized area of 2 cm² using an automatic thicknessmeasuring device (KES-G5 handy compression tester).

“Water absorption capacity” is measured according to JIS K7223-1996“Testing method for water absorption capacity of super absorbentpolymers”.

“Water absorption rate” is the “time that elapses before the end point”measured in accordance with JIS K7224-1996 “Testing method for waterabsorption rate of super absorbent polymers” has been carried out using2 g of superabsorbent polymers and 50 g of physiological salinesolution.

When environmental conditions in tests and measurements are notdescribed, the tests and measurements shall be carried out in a testroom or apparatus under normal conditions (the test location is at atemperature: 20±5° C., relative humidity: 65% or less).

The dimension of each part means the dimension in the spread state, notthe natural length state, unless otherwise stated.

REFERENCE SIGNS LIST

-   -   1 1 liquid impervious sheet    -   12 outer sheet    -   12T target sheet    -   13 fastening tape    -   13A engagement portion    -   13B tape main unit section    -   13C tape attaching portion    -   30 top sheet    -   40 intermediate sheet    -   60 three-dimensional side gather    -   62 gather sheet    -   50 absorber    -   51 front surface side sheet    -   51 c recess    -   52 back surface side sheet    -   53 superabsorbent polymer particles    -   54 bonded portion    -   54 a strong bonded portion    -   54 b weak bonded portion    -   54 c edge bonded portion    -   55 cell    -   55G compartment    -   WD width direction    -   56 empty cell    -   70 anvil roll    -   71 concave    -   72 projection    -   80 first sheet feeding unit    -   81 wave-forming device    -   82 groove roll    -   83 convex roll    -   90 recess forming unit    -   91 push-in pin    -   100 particulate material feeding device    -   150 second sheet feeding unit    -   151 guide plate    -   160 welding unit    -   201 first sheet    -   202 second sheet    -   201 c receiving recess    -   203 particulate materials    -   101 particulate material storage tank    -   102 delivery device    -   103 chute    -   104, 105 blocking body    -   104 first blocking body    -   105 second blocking body    -   106 recovery path    -   121 chute feeding port    -   115 chute discharge port    -   116 partition plate    -   210 cutting position

1. A device for manufacturing an absorber, comprising: an anvil roll,which has a plurality of concaves arranged at intervals on an outerperipheral surface, projections provided in a portion among theconcaves, so as to surround each of the concaves, a suction unitconfigured to suck air in the concaves, without a suction port ordischarge port in the portion among the concaves, and which isrotationally driven around a transverse rotational axis, and the devicefurther comprising a first sheet feeding unit, a receiving recessforming unit, a particulate material feeding device, a second sheetfeeding unit and a welding unit in this order from the upstream side inthe rotation direction of the anvil roll within a range in the rotationdirection of the upper half of the anvil roll, the first sheet feedingunit being configured to feed a continuous belt-shaped first sheet madeof a liquid pervious nonwoven fabric in the rotation direction of theanvil roll along the outer peripheral surface of the anvil roll; thereceiving recess forming unit being configured to form receivingrecesses in the first sheet along the outer peripheral surface of theanvil roll, the receiving recesses being recessed in the concaves; theparticulate material feeding device being configured to drop and feedparticulate materials including superabsorbent polymer particles fromabove to the receiving recesses of the first sheet wound around theanvil roll; the second sheet feeding unit being configured to feed acontinuous belt-shaped second sheet in the rotation direction of theanvil roll, wind the second sheet around the outer side of the firstsheet, and cover at least a range in the cross direction (CD) having thereceiving recesses of the first sheet, with the second sheet; and thewelding unit being configured to weld the first sheet and the secondsheet only at the projections while winding the first sheet and thesecond sheet around the anvil roll, and being provided on the downstreamside of the second sheet feeding unit in the rotation direction of theanvil roll, wherein the suction unit sucks air in the concaves at leastin a range in the rotation direction from a feeding position of theparticulate materials to a feeding position of the second sheet, as theprojections, dot-shaped projections are arranged only in one row atintervals in the direction surrounding each of the concaves, the area ofthe tip end surface of each dot-shaped projection is 8 mm² or less, thewidth in the direction orthogonal to the arrangement direction is 4 mmor less, and peripheral edges of the receiving recesses in the firstsheet coincide with the edges on the receiving recess side of thedot-shaped projections surrounding the receiving recesses.
 2. The devicefor manufacturing an absorber according to claim 1, comprising, as thereceiving recess forming unit, a pushing roll which is opposed to theanvil roll, and which has push-in pins for entering the respectiveconcaves of the anvil roll, wherein a continuous belt-shaped first sheetis passed in the rotation direction of the anvil roll between the anvilroll and the push-in roll, and the first sheet is pushed into theconcaves with the push-in pins to form the receiving recesses in thefirst sheet.
 3. The device for manufacturing an absorber according toclaim 1, comprising a wave-forming device including, a groove rollhaving a plurality of grooves continuing in the roll circumferentialdirection and being arranged in the roll length direction on the outerperipheral surface of the groove roll, a convex roll having a pluralityof continuous convex portions continuing in the roll circumferentialdirection and being arranged in the roll length direction on the outerperipheral surface of the convex roll, and a heating unit wherein thegroove roll and the convex roll being opposed to each other such thatthe grooves and the continuous convex portions are engaged with eachother, and the heating unit heats the first sheet, which passes throughbetween the groove roll and the convex roll, to a melting temperature orlower, wherein the first sheet is passed through between the groove rolland the convex roll of the wave-forming device so that the first sheetis softened by stretching in a waveform in the CD while being heated,and then, the first sheet is fed to the anvil roll by the first sheetfeeding unit.
 4. The device for manufacturing an absorber according toclaim 3, wherein the pushing depth of the first sheet by the push-in pinis 2 to 10 mm, and in the wave-forming by the wave-forming device, thewave height is 1 to 8 mm, and the peak-to-peak interval in the CD is 1to 5 mm.
 5. The device for manufacturing an absorber according to claim1, wherein the feeding position of the particulate materials by theparticulate material feeding device is disposed in a range having therotation angle, with the vertically upward direction as 0°, of 30° ormore, and an angle formed by a horizontal plane and a ridge linepositioned on the most downstream side in the rotation direction of thereceiving recess of the first sheet is 0° or more.
 6. A method formanufacturing an absorber using manufacturing device which comprises: ananvil roll, which has a plurality of concaves arranged at intervals onan outer peripheral surface, projections provided in a portion among theconcaves, so as to surround each of the concaves, a suction unitconfigured to suck air in the concaves, without a suction port ordischarge port in the portion among the concaves, and which isrotationally driven around a transverse rotational axis, the devicefurther comprising a first sheet feeding unit, a receiving recessforming unit, a particulate material feeding device, a second sheetfeeding unit and a welding unit in this order from the upstream side inthe rotation direction of the anvil roll within a range in the rotationdirection of the upper half of the anvil roll, the first sheet feedingunit being configured to feed a continuous belt-shaped first sheet madeof a liquid pervious nonwoven fabric in the rotation direction of theanvil roll along the outer peripheral surface of the anvil roll; thereceiving recess forming unit being configured to form receivingrecesses in the first sheet along the outer peripheral surface of theanvil roll, the receiving recesses being recessed in the concaves; theparticulate material feeding device being configured to drop and feedparticulate materials including superabsorbent polymer particles fromabove to the receiving recesses of the first sheet wound around theanvil roll; the second sheet feeding unit being configured to feed acontinuous belt-shaped second sheet in the rotation direction of theanvil roll, wind the second sheet around the outer side of the firstsheet, and cover at least a range in the CD having the receivingrecesses of the first sheet, with the second sheet; and the welding unitbeing configured to weld the first sheet and the second sheet only atthe projections while winding the first sheet and the second sheetaround the anvil roll, and being provided on the downstream side of thesecond sheet feeding unit in the rotation direction of the anvil roll,wherein the suction unit sucks air in the concaves at least in a rangein the rotation direction from a feeding position of the particulatematerials to a feeding position of the second sheet, as the projections,dot-shaped projections are arranged only in one row at intervals in thedirection surrounding each of the concaves, the area of the tip endsurface of each dot-shaped projection is 8 mm² or less, the width in thedirection orthogonal to the arrangement direction is 4 mm or less, andperipheral edges of the receiving recesses in the first sheet coincidewith the edges on the receiving recess side of the dot-shapedprojections surrounding the receiving recesses, and the methodcomprising: feeding the first sheet to the anvil roll by the first sheetfeeding unit; forming the receiving recesses on the first sheet by thereceiving recess forming unit; feeding the particulate materials to thereceiving recesses of the first sheet by the particulate materialfeeding device; overlapping the second sheet on the first sheet by thesecond sheet feeding unit; bonding the portions among the receivingrecesses of the first sheet and the second sheet by the welding unit tosuccessively form a continuous series of the absorbers in which aplurality of cells containing the particulate materials are arranged;and cutting the continuous series of the absorbers into individualabsorbers at intervals in the machine direction (MD).
 7. The device formanufacturing an absorber according to claim 2, comprising awave-forming device including, a groove roll having a plurality ofgrooves continuing in the roll circumferential direction and beingarranged in the roll length direction on the outer peripheral surface ofthe groove roll, a convex roll having a plurality of continuous convexportions continuing in the roll circumferential direction and beingarranged in the roll length direction on the outer peripheral surface ofthe convex roll, and a heating unit wherein the groove roll and theconvex roll being opposed to each other such that the grooves and thecontinuous convex portions are engaged with each other, and the heatingunit heats the first sheet, which passes through between the groove rolland the convex roll, to a melting temperature or lower, wherein thefirst sheet is passed through between the groove roll and the convexroll of the wave-forming device so that the first sheet is softened bystretching in a waveform in the CD while being heated, and then, thefirst sheet is fed to the anvil roll by the first sheet feeding unit. 8.The device for manufacturing an absorber according to claim 2, whereinthe feeding position of the particulate materials by the particulatematerial feeding device is disposed in a range having the rotationangle, with the vertically upward direction as 0°, of 30° or more, andan angle formed by a horizontal plane and a ridge line positioned on themost downstream side in the rotation direction of the receiving recessof the first sheet is 0° or more.
 9. The device for manufacturing anabsorber according to claim 3, wherein the feeding position of theparticulate materials by the particulate material feeding device isdisposed in a range having the rotation angle, with the verticallyupward direction as 0°, of 30° or more, and an angle formed by ahorizontal plane and a ridge line positioned on the most downstream sidein the rotation direction of the receiving recess of the first sheet is0° or more.
 10. The device for manufacturing an absorber according toclaim 4, wherein the feeding position of the particulate materials bythe particulate material feeding device is disposed in a range havingthe rotation angle, with the vertically upward direction as 0°, of 30°or more, and an angle formed by a horizontal plane and a ridge linepositioned on the most downstream side in the rotation direction of thereceiving recess of the first sheet is 0° or more.